1. Technical Field
The present invention relates generally to an improved recording/reproducing system for recording or reproducing packet data on or from a storage medium and a storage medium on which the packet data is recorded in an unique format.
2. Background of Related Art
Nowadays, digital broadcasting as well as analog broadcasting is put to practical use with development of digital and integrated circuit techniques. In the digital broadcasting, a plurality of programs are transmitted in a time-division multiplexed mode using, for example, unique packets in a DSS (Digital Satellite System) which is in practical use in the United States or transport packets in the MPEG2 format for color moving picture coding in DVB (Digital Video Broadcasting) put to practical use in Europe. Specifically, a broadcasting station (i.e., an encoder) transmits packets of programs at time intervals avoiding overflow or underflow of a buffer memory of a receiver during reception of one of the packets. Therefore, recording a specified one of multiple programs of the digital broadcasting on a storage medium with bit streams requires correct reproduction of the contents of packets and packet intervals (generally called arrival intervals or arrival times).
When consecutive packets are recorded together in real time (e.g., when multiple programs transmitted without any loss of transmission capacity are all recorded by a recording device at a record rate of a similar capacity) or when intermittent packets are recorded, easy reproduction of the contents of packets and time intervals between arrivals of the packets is achieved by filling the time intervals with, for example, dummy data. Alternatively, in a recording device designed to record and reproduce data on and from a hard disc or a memory at higher speed and at random as compared with recording on a magnetic tape, the contents of packets and packet intervals may be recorded and reproduced in a simpler manner.
However, when a specific one of digital TV programs, that is, packets which have arrived intermittently are recorded on a magnetic tape with bit streams, it is necessary to take into account (1) reproduction of original time intervals between arrivals of the packets for reproducing the same signals as the recorded bit streams, (2) an instantaneous change in data rate caused by a variation in packet arriving during a unit time, (3) simplicity of a device such as a buffer memory, and (4) effective utilization of a recording capacity of a magnetic tape traveling continuously.